Erosion is the loss of soil for a multitude of reasons and even though they are dead those trees are helping control that erosion, for a while. Getting something established on that slope to help control erosion is what you need to do and what ever that is should not require mowing.
If, as is common, the previous owners diligently cleaned up those leaves every fall may help explain why the soil is in the condition it is and I would stop cleaning the leaves especially on that slope since the leaf cover can also aid in preventing erosion.

Hi Shelly! Congratulations on your new home. Is that your son doing tai-chi on the lawn?

Cathy

I would get a soil conservationist out there to look at it. Call your county ag extension office and ask them for help with your erosion problem. Tell them it's an eroding creek bank. Or, the NRCS (Natural Resource Conservation Service) which is a federal agency that's part of the USDA I believe.

You could mulch that slope while you're trying to grow stuff on it, too. Can you get straw, shredded yard waste mulch, or somthing like that cheap or free?

Yeah, I was thinking about the county extension office - do they ever make house calls? The yard photographs well, but when I'm mowing out there, I feel like the whole thing needs extensive attention and I'm not sure what is a "have to" and what we can leave alone and it'll be fine. I think this yard may have a steep learning curve to it (har har).

Yep, that's my silly kiddo. If that's a Tai Chi move, it's purely accidental - he was just being his usual flamboyant self!

An excessive amount of leaf cover or mulch can aggravate erosion on that slope.

Naturally slopes would be covered with vegetation to hold soil in place. You need to remove the Maple trees(that probably were landscaped and not necessarily the natural plants that would grow there) and vegetate that slope with native grasses and wildflowers. Use an erosion control blanket to hold the seed in place until the vegetation establishes.

Contacting the NRCS is a good suggestion, however if you are in a residential area they may not be able to help you...as their focus in most states is primarily in rural/agricultural areas.

You should seriously consider a buffer between the yard areas and the creek areas. You don't want to plant turf grass on the slope or within 20'-40' of the slope. Also considering minimizing the amount of turf grass that you grow... and think about a more native landscape, it has a deeper more fibrous root structure to hold soil in place and doesn't need mowing.

Turf grass doesn't make for good erosion control. Unless you are golfing or playing football, reconsider trying to establish turf and opt for a more natural ground cover that will prevent erosion.

The native plants are adapted to grow in the existing soil, they don't need any soil amendments either.

A good resource can be a local chapter of a Native Plant Society or if you have a Wild Ones in the area. Tell them you are looking for help establishing native plants in a riparian area. You may be able to get volunteer help and donated plants and seeds to help you re-establish this area to a more natural stable condition.

Is there a local watershed group, they may be helpful also.

http://www.wildonesniagara.org/

http://www.newenglandwild.org/

Here is a link that might be useful: Riparian Area Management

Wow Joe! That was quite a posting! I'm feeling a little overwhelmed right now...more than before. The slope itself is a whopping mess. There is decades of yard waste down there (complete with every critter imaginable), there are heavy vines choking the trees that are still standing, and there is obvious, serious erosion that has taken place over the years. The previous owner said than when his kids were little that there were stairs going down to the creek, but there's no evidence of the stairs now, nor is there an obvious place where one could put stairs. Plus, the previous owner installed his own horseshoe pits years ago (I know! Who does that?), and if you stood where you were supposed to to actually play a game, you'd fall right over. So that tells us a lot about how fast this spot is eroding. I actually wonder if the next door neighbor's house will still be there in a few years. The house is only about 10-15 feet away from the slope and their section is steeper than ours. Although they don't have a fraction of the yard waste on their side that we do. We've pulled tons of old metal and an old tire out of another part of the yard that's woodsier and way less eroded, so I don't even want to think about what's down there besides yard waste.

There's one area, right at the edge of the yard that's basically bare dirt with a smattering of weeds. If I only put some native plants in that spot and did nothing else (I'm thinking about the slope), would that slow the erosion down any? And even in that spot, you wouldn't amend the soil or add compost or anything? Would you bring in any top soil?

Thanks so much for the links you sent. That Riparian Area Management page is fascinating. I called the extension office and they gave me the number of the soil and water division. I've left a message at that office, but they haven't called back yet. I just this second googled "watershed cazenovia creek" and came back with this link:

http://www.epa.gov/ecopage/rivers/cazcreek/index.html

It looks like I have a few places to turn, at least to learn something - prior to today, I'd never even heard the word "riparian" before, so I'm already making progress!

Forgive me for really hoping you're wrong about those sugar maples.... :)

I went out and took some pictures of the yard tonight - they show the erosion better than I can describe it. How bad is it, Doc? Give it to me straight.

Here is a link that might be useful: Shelly's Erosion pics

Someone mentioned that the county extension agent may not be able to help if you're in a residential area. If that is the case you may have local city or county stormwater office that could help also. I don't know how big your municipality is...

At least you're on the right path, knowing that you want to do something. I think Jpw's got the right idea, native and no mow.